Chris Morriss wrote:

So, improved fidelity of the bass waveform, then. Do drivers
typically have inconsistencies in response that are dependent on the
direction the cone moves in?

Well they shouldn't have of course!

In general the magnetic flux isn't symmetrical each side of the cone
resting position, so drivers do produce even-order distortion even at
low levels. At high levels more non-linearities come into play of
course as the cone hits mechanical limits, and the coil comes out of
the main flux area of the magnet gap.

Got the idea. Many years ago, I once heard a pair of Linn Isobariks in Russ
Andrews and thought the bass was amazingly solid and clear. Someone else was
auditioning, I was just milling about. I think it was a jazzy track with
acoustic bass.

Maybe this isobarik idea is worth pursuing instead of the transmission
lines...


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

In message , Wally
writes
Chris Morriss wrote:

So, improved fidelity of the bass waveform, then. Do drivers
typically have inconsistencies in response that are dependent on the
direction the cone moves in?

Well they shouldn't have of course!

In general the magnetic flux isn't symmetrical each side of the cone
resting position, so drivers do produce even-order distortion even at
low levels. At high levels more non-linearities come into play of
course as the cone hits mechanical limits, and the coil comes out of
the main flux area of the magnet gap.

Got the idea. Many years ago, I once heard a pair of Linn Isobariks in Russ
Andrews and thought the bass was amazingly solid and clear. Someone else was
auditioning, I was just milling about. I think it was a jazzy track with
acoustic bass.

Maybe this isobarik idea is worth pursuing instead of the transmission
lines...


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.




Never experimented with Isobarics. It's a good way of getting the Q low
in a small cabinet, but the efficiency is very low too.

I like transmission lines, but they do have to be big and if the line
isn't adequately damped they have a pronounced wavy ripple in the
response. I used to have a pair of the old TLS50 speakers and they were
excellent if raised off the floor by 4 inches or so. (Sitting directly
on the floor the bass was a bit muddy).

Now 'muddy' I understand as a bass description, still wondering about
'slam' though :-)

I'm sure that TL speakers are far too genteel to have slam!
--
Chris Morriss

In message , Wally
writes
Chris Morriss wrote:

So, improved fidelity of the bass waveform, then. Do drivers
typically have inconsistencies in response that are dependent on the
direction the cone moves in?

Well they shouldn't have of course!

In general the magnetic flux isn't symmetrical each side of the cone
resting position, so drivers do produce even-order distortion even at
low levels. At high levels more non-linearities come into play of
course as the cone hits mechanical limits, and the coil comes out of
the main flux area of the magnet gap.

Got the idea. Many years ago, I once heard a pair of Linn Isobariks in Russ
Andrews and thought the bass was amazingly solid and clear. Someone else was
auditioning, I was just milling about. I think it was a jazzy track with
acoustic bass.

Maybe this isobarik idea is worth pursuing instead of the transmission
lines...


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.




Never experimented with Isobarics. It's a good way of getting the Q low
in a small cabinet, but the efficiency is very low too.

I like transmission lines, but they do have to be big and if the line
isn't adequately damped they have a pronounced wavy ripple in the
response. I used to have a pair of the old TLS50 speakers and they were
excellent if raised off the floor by 4 inches or so. (Sitting directly
on the floor the bass was a bit muddy).

Now 'muddy' I understand as a bass description, still wondering about
'slam' though :-)

I'm sure that TL speakers are far too genteel to have slam!
--
Chris Morriss

"Wally" wrote in message
...

Rather than the idea I mooted recently about making compact transmission
lines using Kef B139s and driving them with a filtered signal to provide
lift where the speakers roll off, I have another option - I have a total
of
four B139s, two in the existing speakers, and two bought as spares and/or
drivers for the future bass units.

Am I right in thinking that some sort of push-pull set up will give me a
shallower roll-off for a given size? What design approaches are there, and
how do they compare?

The simple fact is that by modern standards, B139s are pretty mediocre
subwoofer drivers. They were never much more than fairly good plain old
woofers.

*real* subwoofer drivers don't need kludges like "isobaric" cabinets to
outperform any reasonable requirements.

If money is tight, auction off the B139s and use the cash to buy a real
subwoofer driver.

Oh, and if you are building a subwoofer, forget transmission lines. They are
basically a waste of good box volume.

"Wally" wrote in message
...

Rather than the idea I mooted recently about making compact transmission
lines using Kef B139s and driving them with a filtered signal to provide
lift where the speakers roll off, I have another option - I have a total
of
four B139s, two in the existing speakers, and two bought as spares and/or
drivers for the future bass units.

Am I right in thinking that some sort of push-pull set up will give me a
shallower roll-off for a given size? What design approaches are there, and
how do they compare?

The simple fact is that by modern standards, B139s are pretty mediocre
subwoofer drivers. They were never much more than fairly good plain old
woofers.

*real* subwoofer drivers don't need kludges like "isobaric" cabinets to
outperform any reasonable requirements.

If money is tight, auction off the B139s and use the cash to buy a real
subwoofer driver.

Oh, and if you are building a subwoofer, forget transmission lines. They are
basically a waste of good box volume.

In article ,
Arny Krueger wrote:
If money is tight, auction off the B139s and use the cash to buy a real
subwoofer driver.

Oh, and if you are building a subwoofer, forget transmission lines. They
are basically a waste of good box volume.

More sacrilege from Arny. But true. I've never come across a pro
transmission line speaker, and for good reasons.

--
*It's a thankless job, but I've got a lot of Karma to burn off

Dave Plowman London SW 12
RIP Acorn

In article ,
Arny Krueger wrote:
If money is tight, auction off the B139s and use the cash to buy a real
subwoofer driver.

Oh, and if you are building a subwoofer, forget transmission lines. They
are basically a waste of good box volume.

More sacrilege from Arny. But true. I've never come across a pro
transmission line speaker, and for good reasons.

--
*It's a thankless job, but I've got a lot of Karma to burn off

Dave Plowman London SW 12
RIP Acorn

Arny Krueger wrote:

The simple fact is that by modern standards, B139s are pretty mediocre
subwoofer drivers. They were never much more than fairly good plain
old woofers.

Where does it say that I have to adhere to modern standards? I 'eard 'em in
the Linns and they sounded better than my room can do justice to, so why
should I want to go even better?


*real* subwoofer drivers don't need kludges like "isobaric" cabinets
to outperform any reasonable requirements.

Name a driver, and enclosure design/volume, that you recommend instead.


If money is tight, auction off the B139s and use the cash to buy a
real subwoofer driver.

If I did that, there'd be big holes in my present speakers.


Oh, and if you are building a subwoofer, forget transmission lines.
They are basically a waste of good box volume.

Looks like I'll have to scupper the Nautilus copies built out of plywood and
car body filler, then...


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Arny Krueger wrote:

The simple fact is that by modern standards, B139s are pretty mediocre
subwoofer drivers. They were never much more than fairly good plain
old woofers.

Where does it say that I have to adhere to modern standards? I 'eard 'em in
the Linns and they sounded better than my room can do justice to, so why
should I want to go even better?


*real* subwoofer drivers don't need kludges like "isobaric" cabinets
to outperform any reasonable requirements.

Name a driver, and enclosure design/volume, that you recommend instead.


If money is tight, auction off the B139s and use the cash to buy a
real subwoofer driver.

If I did that, there'd be big holes in my present speakers.


Oh, and if you are building a subwoofer, forget transmission lines.
They are basically a waste of good box volume.

Looks like I'll have to scupper the Nautilus copies built out of plywood and
car body filler, then...


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Dave Plowman wrote:
In article ,
Arny Krueger wrote:
If money is tight, auction off the B139s and use the cash to buy a
real subwoofer driver.

Oh, and if you are building a subwoofer, forget transmission lines.
They are basically a waste of good box volume.

More sacrilege from Arny.

Is that a synonym for 'trollage'?


But true. I've never come across a pro
transmission line speaker, and for good reasons.

For reasons of volume, as Arny states?


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.